A great existing Digital Toolbox (specifically for science and math);
digitaltoolbox
digitaltoolbox

Good sources for standards-based lesson plans;
Sources for creating rubrics for both classroom and lab [[#|work]];
Good source for classroom games;
Source for current topics which may be integrated into lesson plans;
Useful sources for MSDS / right-to-know data sheets for chemicals;
Source for test [[#|questions]], including those designed to uncover misconceptions;
Example of a HS science teacher blog and Twitter page;